JPS60111665A - Golf ball - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for projecting each ridge line of a regular octahedron onto a spherical surface circumscribing a regular octahedron, and using the projection line as a virtual dividing line that evenly divides the spherical surface. Regarding golf balls in which dimples are arranged completely or almost equally (hereinafter referred to as an octahedral dimple arrangement pattern), the total number of dimples is optimized in order to improve the elongation in the low-velocity region from the highest point of the trajectory to the drop. This is a golf ball that has made a difference.

[Prior art]

The dimple arrangement pattern and total number of dimples on golf balls have conventionally been broadly classified into the following five types.

(2) It has about 336 dimples (1) arranged in a regular octahedron as shown in Fig. 3 (in the drawing, the dimples are shown on the spherical surface (hereinafter referred to as blank space)).

■ In order to make the icosahedron consistent at the parting line, it has about 332 dimples, which is still called an icosahedron by removing the - column.

■ Approximately 330 to 344 concentric circles or a concentric arrangement
with dimples.

■ It has 360 dimples arranged in a regular dodecahedron.

■It has 252 dimples arranged in a regular icosahedron.

Among the above, ■■ has a problem in terms of directionality because the only plane of symmetry that includes the center of the ball is the parting plane, and the spherical equivalence is low.

■■■ projects each edge of the regular polyhedron onto the spherical surface that circumscribes the regular polyhedron, sets the projection line to the spherical surface as a virtual dividing line (2) of the spherical surface, and divides the sphere using this virtual dividing line (2). Dimples are arranged in an almost identical pattern on each spherical section (3), and the plane containing each virtual dividing line (2) and the center of the sphere is the plane of symmetry of the ball. A ball with equivalence to a regular polyhedral edge lattice like this has less in-plane directionality (anisotropy) (, which is better than .

However, in the case of ■■, each plane of symmetry including the center of the ball does not intersect at right angles, so there is no orthogonal symmetry, so it is difficult to tee up the ball when taking a tee shot, it is difficult to address the ball, and it is difficult to adjust the line when putting. The difficulty of matching has become a negative factor, and it has not yet been fully accepted.

Since the regular octahedral edge lattice equivalence shown in (2) has orthogonal symmetry, it is a traditional pattern that does not have the drawbacks mentioned in (1) and is still the mainstream for golf balls.

In the case of this regular octahedral dimple arrangement pattern, most have 336 dimples, although there are some increases and decreases due to differences in brand printing space.

On the other hand, one of the requirements for golf ball dimples is to prevent the transition from turbulent flow separation to laminar flow separation of the air layer in the low-velocity region from the highest point of the golf ball's trajectory to its fall. One example is to make the dimple edges long. This is caused by increasing the dimple diameter.
This can be done by increasing the number of dimples or by a combination of both.

Therefore, in order to produce the above effect in the ball having 336 dimples mentioned in (2) above, it is possible to increase the dimple diameter, but in the case of this dimple arrangement, the arrangement pitch (4
) varies depending on the location, but in a narrow place it is 3.9 T.
In the case of a small ball with a diameter of 4,115 mm and no nL, it was not possible to make the dimples large enough due to the combination with the number of dimples.

In view of the above circumstances, the present invention provides a golf ball with a regular octahedral dimple arrangement pattern in which the total number of dimples is 400 to 5.
50, it is an object of the present invention to provide a golf ball that can improve the elongation of the golf ball in a low speed region and increase flight distance.

The present invention will be specifically described below based on embodiments shown in the drawings.

The elongation of a golf ball's trajectory in the low-speed region from its highest point to its fall is greatly influenced by the size of the ball, dimple diameter, and number of dimples.Experiments have shown that the larger the value, the better the result. It was revealed by.

K = D X N/R2・・・・・・・・・・・・(
1) It has also been found that the following α value is preferably in the range of 500 to 1000.

D: Dimple diameter N: Total number of dimples R: Golf ball diameter Ek: Diameter dimension at a point down from the dimple edge in the micron depth direction (apparent diameter when cut parallel to the opening diameter surface of the dimple edge) n: By the way, the conventional octahedral dimple arrangement pattern shown in Fig. 3 is 336 mm (dimple depth unit: micron).
For a small ball with a diameter of 41.15 mm and having 41.15 mm dimples, the distance between dimple centers at the point where one dimple is closest to the next dimple, that is, the dimple pitch (4), is approximately 39 pitches, and D = 3.9. Then, K=0.774.

If the dimple diameter is set to 3.9 or more, adjacent dimples will overlap, so the maximum value is 0774.

If the number of dimples (1) is increased to 416 without breaking the octahedral dimple arrangement pattern as shown in Figure 1, D
= 3.5, in which case the K value is 0.
860, which is 11% compared to the one with 336 dimples.
Up.

Furthermore, as the number of dimples increases without breaking the octahedral dimple arrangement pattern, the value increases, and the elongation of the ball's trajectory from the highest point to the point of fall improves.
When the number of dimples is increased beyond 550, the dimple pitch becomes 2.87+++ m or less, and the diameter becomes 2.8 wn.
Only the following small dimples can be placed.

In addition, in order to fit within the α value range of equation (2), a shallow dimple with a depth of 015 or less is required. When shots are repeated, the dimple shape changes greatly, and the initial performance differs from that after several uses. This is undesirable because it causes a difference in performance. A dimple count of about 400 to about 550 is optimal.

This invention is most effective for balls that do not spin easily, such as two-piece balls, but it can of course be applied to thread-wound balls and one-piece balls.

The table below is a comparison between specific embodiments of the present invention and conventional examples.

[Brief explanation of the drawing]

FIG. 1 is a front view of a golf ball according to the present invention, FIG. 2 is an enlarged sectional view of a dimple, and FIG. 3 is a front view of a conventional golf ball. (1)...Dimples (2)...Virtual lot line Applicant: Sumitomo Rubber Industries, Ltd. Procedural amendment 0 direction Illusion February 1985 19B T, Y Governor's Palace 2, Name of invention Golf ball 3 , Person making the amendment Name of the client (4) Figures 4 to 6 in the drawings of Sumitomo Rubber Industries, Ltd. (2) have been supplemented as attached. Description 1, Name of the invention Golf ball 2 , Claims■ In a golf ball in which a plurality of dimples are formed in each spherical surface division part surrounded by virtual division lines dividing the spherical surface into eight equal parts or in an almost identical arrangement pattern, the number of dimples is 400. ~550 dimples and adjacent dimples do not overlap; a golf ball having the following α value in the range of 500 to 1000. Here, R: diameter of the golf ball (fitness) N: number of dimples Ek: Diameter dimension at a point down from the dimple edge in the micron depth direction (apparent diameter of the dimple when cut parallel to the opening diameter surface of the dimple edge) (n: dimple depth in microns) ■ The total number of dimples is 416. The golf ball according to claim 1 or 2, wherein the dimples have an average diameter of 32 to 3.6 dimples. (2) The golf ball according to claim 1 or 2, having a total number of dimples of 528 and an average dimple diameter of 29 to 3.2 dimples. 3. Detailed Description of the Invention The present invention provides a method for projecting each ridge line of a regular octahedron onto a spherical surface circumscribing the regular octahedron, and using the projection line as a virtual division line that evenly divides the spherical surface. Regarding golf balls in which dimples are arranged completely (or almost equally) (hereinafter referred to as a regular octahedral dimple arrangement pattern), the total number of dimples is This is an optimized golf ball. [Prior Art] The dimple arrangement pattern and total number of dimples on a golf ball have conventionally been broadly classified into the following five types: ■ Regular octahedral arrangement as shown in Figure 3. (In the drawing, the dimples are shown in % of the spherical surface.) ■ Symmetrical on the perphic line, and generally has about 332 dimples in an icosahedral arrangement. ■ Approximately 330 to 344 concentric circles or a concentric arrangement
with dimples. ■ It has 360 dimples arranged in a regular dodecahedron. ■ One with 252 timples arranged in a regular icosahedron. Among the above, ■■ has a problem in terms of directionality because the only plane of symmetry that includes the center of the ball is the parting plane, and the spherical equivalence is low. ■■■ projects each edge of the regular polyhedron onto the spherical surface that circumscribes the regular polyhedron, sets the projection line to the spherical surface as a virtual dividing line (2) of the spherical surface, and divides the sphere using this virtual dividing line (2). Dimples are arranged in an approximately equal pattern on each spherical division (3), and the plane containing each virtual dividing line (2) and the center of the sphere is the plane of symmetry of the ball. A ball with regular polyhedral edge lattice equivalence has less in-plane directionality (anisotropy) and is better than ■■. However, in the case of ■■, the planes of symmetry including the center of the ball do not intersect at right angles, and there is no orthogonal symmetry, making it difficult to tee up and address the ball when taking a tee shot, and it is difficult to match the lines when putting. The fact that it is difficult has become a negative factor, and it has not yet been fully accepted. Since the regular octahedral edge lattice equivalence shown in (2) has orthogonal symmetry, it is a traditional pattern that does not have the drawbacks mentioned in (1) and is still the mainstream for golf balls. In the case of this regular octahedral dimple arrangement pattern, most have 336 dimples, although there are some increases and decreases due to differences in brand printing space. On the other hand, the golf hole flies at a high speed of 40 to 80 m/sec, but during that time it flies at a speed of 2,000 to 10 m/sec. It is a sphere that rotates at a high speed called OOORPM. One of the roles of the dimples formed on this spherical surface in terms of physical performance is to obtain the final gain in flight distance, including the trajectory shape in the low-velocity region from the highest point to the drop during ball flight. An example of this is to move the transition point to turbulent flow separation to a lower speed region as much as possible. In order to prevent the transition from turbulent flow separation to laminar flow separation of the air layer in this low velocity region, it is proposed to make the dimple edge as long as possible. This can be done by increasing the diameter of the dimples, increasing the number of dimples, or a combination of both. Therefore, in order to produce the above effect in the hole having 336 dimples mentioned above, it is possible to increase the dimple diameter, but in the case of this dimple arrangement, the arrangement pitch (4
) may vary depending on the location, or there are only 39 votes in a narrow area, and in the case of a small size ball with a diameter of 41.15+l1ll+, it was not possible to make the dimples that large due to the combination with the number of timples. In view of the above-mentioned circumstances, the present invention has revealed a golf hole with a well-balanced shape, total number, and arrangement of dimples, which improves elongation in the low-speed region from the highest point to the fall of the ball during flight, and increases flight distance. The purpose is to provide golf balls. Another object of the present invention is to provide a regular octahedral dimple array pattern golf ball having a total number of 400 to 550 dimples, thereby achieving the above object. The present invention will be specifically described below based on embodiments shown in the drawings. The elongation of a golf ball's trajectory in the low-speed region from its highest point to its fall is greatly influenced by the size of the ball, dimple diameter, and number of dimples.Experiments have shown that the larger the value, the better the result. It was revealed by. K = D x N/R (1
) It has also been found that the following α value is preferably in the range of 500 to 1000. ct = (:E:(Ek-IXElc) + 2x
kg, gk") (Diameter) n: Dimple depth (unit: micron) When the dimple is circular, the "dimple diameter" used here refers to the diameter of the tangent circle of the dimple formed on the plane when an imaginary plane is placed on the dimple. Alternatively, when the dimple is cut with a cross section passing through the dimple center and the ball center, a tangent line passing through both edges of the dimple is drawn, and the distance between the two contact points is taken as the dimple diameter. If the dimple is not circular, it is replaced with a circular dimple having a circumference equivalent to the total extension line of the shape formed by the dimple edge, and its diameter is taken as the dimple diameter. As used herein, "dimple depth" refers to the distance from the horizontal plane including the dimple edge to the deepest position within the dimple. The "dimple pitch" used here refers to the center distance between this dimple and all adjacent dimples when focusing on a dimple on the spherical surface of the ball. The distance refers to the length of a large arc connecting two projection points when the centers of two dimples are projected onto the ball's spherical surface. The α value is an index of dimple size, n-1n
-12 So, in equation (2) above, kz k (E k-LX E
k)+2X In k, Ek is an approximate value of the effective volume per dimple. To briefly explain this approximate calculation, as shown in Fig. 4, the volume ΔV ( mm3) is expressed by the following formula: Δv=0.001π(Ek-(+Ek-1・EIc-1
−Ek2)2 Effective volume for a dimple with a depth of n microns, AΔ
Subtracting the approximate value of
k ), and omitting the constant part (0,001, , 2), the above calculation formula can be obtained. If the dimple shape is circular, the following can be said: The diameter and depth of the dimple are constant. When the number of dimples is large, the α value is large, and when the number of dimples is small, the α value is small. When the diameter and number of dimples are constant, the deeper the dimples, the larger the α value, and the shallower the dimples. When the depth and number of dimples are constant, increasing the dimple diameter increases the α value, and decreasing the dimple diameter decreases the α value. By the way, the conventional positive Diameter 41.15 with 336 dimples in an octahedral dimple array pattern
For a small ball of mm, the distance between the centers of the timples at the point where the dimples are closest to the adjacent dimples, that is, the distance between the dimples (4) is approximately 39 mm, and the D
= 3.9, then K=0.774. If the dimple diameter is set to 3.9 or more, adjacent dimples will overlap, and the maximum value is 0774. If the number of dimples (1) is increased to 416 without breaking the octahedral dimple arrangement pattern as shown in Figure $1, D
-35, in which case the K value is 0.860
This is an increase of 11% compared to the one with 336 dimples. Historically, the value increases as the number of dimples increases without breaking the octahedral timple number sequence pattern, and the trajectory of the hole increases from the highest point to the point of fall. If the number of dimples is increased beyond 550, the pitch of the dimples becomes less than 287 mm, and only small dimples with a diameter of 2.8 mm or less can be arranged. In addition, in order to keep the α value in the range of equation (2), it is necessary to create a shallow dimple with a depth of 0.15 mm or less, and if the slope and throat are repeated, the dimple shape changes greatly and the initial performance differs several times. This is not preferable because it causes a difference in performance after use. A timple count of about 400 to about 550 is optimal. Note that various methods of arranging the octahedral dimples can be considered in multiples of 8. However, in order to obtain a dimple pitch with little variation, the total number of dimples should be 4.
16 or 528 pieces are desirable. For a golf ball with a diameter of 42.67 mm and a total number of dimples of 4-16, the pitch between dimples is 3.7-
It is within the range of 4.2 mm. For a golf ball with a diameter of 42.67 mm and a total number of dimples of 528, the pitch between dimples is 3.2 to 3.
．． 6 rrtm. Next, Examples will be given to demonstrate that the golf ball according to the present invention has excellent flight distance. The flight distance test was conducted by setting a No. 1 wood of a golf club on a hitting test machine and hitting a golf ball at a speed of 45 m for 7 seconds. The numerical values shown in the test results in Tables 1 to 3 are obtained by testing eight samples twice and taking the total average value. In Tables 1 to 3, the words and phrases are explained as follows. Flight distance (carry): The distance the ball travels from the point of impact until it falls to the ground Rolling (run) The distance from the point where the ball falls to the ground until it stops (total) The total flight distance including carry and run Trajectory Shape 2: ``Good'' means that the ball has some elasticity after hitting the ball, and ``Ho-knob ball'' means that the ball is floating after hitting the ball.
Nikari: [Bobball] refers to a ball that does not stretch after being hit and ends up bowing. Example 1 A flight distance test was conducted on a thread-wrapped ball with a diameter of 41.2 mm. Test results first
Shown in the table. Note that Samples Nos. 1-5 are golf holes according to the present invention, and Samples Nos. 5 and 101-112 are golf holes prepared for comparison. Samples No. 8, 1-5, 111 and 112 are golf balls with a total number of dimples of 416, and the relationship between the total flight distance and α value is plotted for Samples No. 3, 1-3, 111 and 112. It is shown by line AA in Figure 5. As is clear from Table 1, Sample No. 3, 1-4 (number of timples 416, dimple diameter approximately 3.45 rrvn
) is the number of dimples of sample NO3, 101-110, 33
Compared to the 6-piece ball, the total flight distance is more than 5 meters, and the trajectory shape of the ball is such that it rises and hops near the highest point of the trajectory, and it is ball-shaped and drops as if it had been held down from the ground up. It has a good trajectory with good length and extension. Further, since the ball of sample No. 5 has a small value, the total flight distance is slightly inferior to that of samples no. 8, 1-4, but is superior to that of samples no. 8, 101-110. In addition, sample No. 111 and No. 112 are sample No. 8
, the value is about the same as 1-4, or the α value is 500-10
00, and the total flight distance was 1ii11, which is inferior to the golf ball of the present invention. □21 tanks "1GO-111665 (8ゝHo" diameter force 4
A flight distance test was conducted on a two-piece ball of 1.2 wA. The test results are shown in Table 2. In addition, sample No. 8
, 5-8 are golf balls according to the present invention, and sample No.
No. 8,113-119 are golf balls prepared for comparison. The relationship between the total flight distance and the α value for samples Nos, 5-8, 118 and 119 is plotted and shown by the BB line in FIG. As is clear from Table 2, Sample No. 8, 6-8 (number of dimples 416, dimple diameter approximately 3.45 rrvn
) is sample Nos, the number of dimples of 113-117 is 33
Compared to the six-piece model, it has an advantage in total flight distance of more than 6m and a good trajectory. Note that samples No. 5, 118, and 119 have 4 dimples.
Sample No. 16 has a value similar to that of sample No. 8, 5-8, but α
Since the value deviates from the range of 500-1000, the total flight distance is inferior to the golf ball of the present invention. Example 3 A flight distance test was conducted on a thread-wound balata covered ball with a ball diameter of 42.7 wtrs. The test results are shown in Table 3. Note that samples Nos. 8 and 9-11 are golf balls according to the present invention, and samples Nos.
6 is a golf ball prepared for comparison. Regarding samples NO8, 9'-11, 125 and 126,
A plot of the relationship between the total flight distance and the α value is shown by the line CC in FIG. As is clear from Table 3, sample NO! +, 9-11 (number of dimples: 416, dimple diameter: approximately 355) has an advantage over sample No. 8, 120-126, which has 336 dimples, by more than 5 m in total flight distance and a good trajectory. are doing. Incidentally, samples Nos. 8, 1, 25 and 126 have a dimple number of 416 and a value similar to that of samples Nos. 8, 9-11, but the α value deviates from the range of 500-1000, so they cannot be used as golf balls of the present invention. It is inferior in total distance compared to. In order to confirm the importance of limiting the α value to a range of 500-1000, a wind tunnel experiment was conducted and the results are shown in FIG. The wind tunnel experiment was conducted using known means.
d ings969 of 19th Japan National Co
ngress for Applied M=chmP
167-P 170). In addition, one point in Fig. 6 represents 4 golf balls under 6 Raynozzle number conditions and 4 spin conditions, 3 each for a total of 24 conditions.
Statistically regression the curve from a total of 288 points each time, and from the curve, Ray nozzle number 1.5XlO, spin 4000 RPM
This is the value read. Further, the drag coefficient index and the lift coefficient index are expressed as a ratio of the lift coefficient of a sample having an α value of 700. In the case of a golf ball, it is generally believed that the larger the lift coefficient and the smaller the drag coefficient, the better the aerodynamic characteristics of the lift coefficient and drag coefficient obtained in wind tunnel experiments. In particular, since the weight of the drag coefficient is large, it is most desirable to have the drag coefficient in the vicinity of α-600 to α-800, which is the lowest in FIG. Also, α-600~8 in terms of the high lift-drag ratio.
A range of 00 is also valid. Furthermore, it is generally known that even if the lift coefficient is a little low, as long as the drag coefficient is small, the trajectory of the golf ball is not bad. Therefore, if the lift coefficient index is 0.
．． Considering the conditions of 6 or more and a drag coefficient index of 1.5 or less, it can be said that an α value in the range of 500 to 1000 is favorable. If the α value is less than 500, the lift coefficient will be high, but the drag coefficient will also be large, which will only lead to a loss in flight distance (the trajectory will also vary. Depending on the ball diameter and structure, the optimal range will gradually shift, or the α value will be 500~ It can be said that a range of 1000 is desirable. 4. Brief description of the drawings FIG. 1 is a front view of the golf ball according to the present invention, FIG. 2 is an enlarged sectional view of the dimples, and FIG. 3 is a front view of the conventional example. Figure 4 is an enlarged cross-sectional view of the dimple, Figure 5 is a graph showing the correlation between α value and total flight distance, and Figure 6 is a graph showing the correlation between α value and aerodynamic characteristic values based on wind tunnel experiments. ( 1) Dimple (2) Virtual lot line applicant Sumitomo Rubber Industries, Ltd.

Claims (1)

[Scope of Claims] ■ In a golf ball in which a plurality of dimples are formed in each spherical surface division part surrounded by virtual division lines dividing the spherical surface into eight equal parts or in an almost identical arrangement pattern, the number of dimples is A golf ball characterized in that there are 400 to 550 dimples and adjacent dimples do not overlap. ■ α value below R: Diameter of the golf ball N: Total number of dimples Ek: Diameter dimension at a point down from the dimple edge in the micron depth direction (when cut parallel to the opening diameter surface of the dimple edge) The golf ball according to claim 1, wherein the apparent diameter (b): dimple depth (microns) is in the range of 500 to 1000. (2) The golf ball according to claim 1 or 2, having a total number of dimples of 416 and an average dimple diameter of 32 to 3.6111 m. (2) The golf ball according to claim 1 or 2, having a total number of dimples of 528 and an average dimple diameter of 29 to 3.2 groups.